1. Field of the invention
The present invention relates to an improved sampling device allowing one to collect separately gas and aerosol pollutants contained in polluted air, and to a method of use of this device.
2. Brief description of the prior art
U.S. Pat. No. 4,689,059 describes a device for cleaning harzardous or toxic solid and liquid substances and for effectively retaining the macro- and micro-particles of the substance along with any vapor generated thereby. This device generally comprises a vacuum cleaner having a housing and an arrangement for drawing a fluid flow from an inlet to an outlet of the housing. A first filter is provided for separating and retaining both macro- and micro-particles of the substance entrained with the fluid flow. The first filter is arranged on a downstream side of the inlet of the housing and has a reservoir portion arranged below the inlet. Walls of the first filter permit outflow of substantially only vapors of the substance entrained in the fluid flow. A second filter for retaining the vapors is arranged fluidically between the first filter and the outlet. This second filter is advantageously a carbon filter. In a particularly preferred embodiment, the first filter includes a microporous filter membrane which is laminated to a fibrous support to provide a self-supporting unitary first filter for accomplishing the separation of the macro- and micro-particles of the substance. Advantageously, this first filter is made with polytetrafluoroethylene especially a polytetrafluoroethylene filter of the type described in U.S. Pat. No. 4,187,390.
Also, as evidenced by U.S. Pat. Nos. 4,178,794; 4,350,507 and 4,455,881, there presently exists various types of devices to be worn by workmen for measuring the quantity of airborne particles in a given area of work.
More particularly, U.S. Pat. No. 4,178,794 describes a device intended to be worn on a workmen's chest. This device comprises a cartridge provided with an inlet, an outlet and an air filter, the inlet of the cartridge being connected to a cyclone which separates respirable and non-respirable airborne particles, while the outlet of said cartridge is connected to a portable vacuum pump.
U.S. Pat. No. 4,350,507 describes a device intended to be suspended either in front of a worker by use of straps passing around his neck and waist, or as an integral part of a helmet worn by said workman. This device comprises a housing defining an air passageway, an electric fan mounted in the passageway, a main filter located across the passageway to collect respirable airborne particles and a prefilter located across the passageway upstream of the main filter, to collect non-respirable airborne particles.
U.S. Pat. No. 4,455,881 describes a device intended to be worn by a workman for sampling respirable aerosols contained in an ambient atmosphere. This device comprises a selector capillary tube open at one end thereof to the atmosphere, a sampling capillary tube in fluid communication with the other end of the selector tube, and aspiration means in fluid communication with the sampling tube.
U.S. Pat. No. 4,721,517 describes a sampling device for collecting at least part of the airborne particles in a workman's breathing zone, said device being of the type comprising a cartridge provided with an inlet, an outlet and an air filter (e.g. a membrane of polyvinylchloride (PVC) or a membrane of cellulose esters having a porosity of about 0.8 .mu.m), a vacuum pump and a piece of flexible tubing of determined length connecting the vacuum pump to the outlet of the cartridge so that a portion of the airborne particles in said breathing zone is drawn through said filter and is collected thereon.
Until now, there have been no devices nor methods for the separate collection of gaseous and aerosol pollutants contained in polluted air in order to make possible, thereafter, the quantitative determination of the amount of gaseous and aerosol pollutants that were contained in said polluted air.